Spread spectrum multipath receiver without a tracking loop
US6014405A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 24, 1997 |
| Grant date | Jan 11, 2000 |
| Priority date | — |
| Expiry date | Oct 24, 2017 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04B1/7115
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
An improvement to a receiver for receiving multiple rays, due to multipath, of a received spread-spectrum signal having a chip-sequence signal with a chip rate embedded therein. The received spread-spectrum signal is sampled by an analog-to-digital converter at approximately twice the chip rate and then the samples are shifted in a shift register. The shift register shifts the chips of the underlying chip-sequence signal at approximately twice the chip rate. A matched filter includes an adder tree which, in cooperation with the shift register, forms an impulse response matched to the chip-sequence signal. The adder tree detects initially the chip-sequence signal embedded in the first ray, and outputs a first correlation signal. The adder tree then detects the chip-sequence signal embedded in the second ray, and outputs a second correlation signal. The adder tree continues to detect the chip-sequence signal of subsequent rays, and outputs subsequent correlation signals. A combiner combines each of the correlation signals using maximal-ratio combining. No tracking loop is required even though the chip clock and the sampling clock have slightly different frequencies.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.